single reducton clamping gearbox CAD

Does anyone happen to know where I can find a CAD model (stp file) for the vex pro single reduction clamping gearbox (with the omni wheels pictured next to the gearbox model on the website) I can’t seem to find it (we are using inventor pro 2015).

http://content.vexrobotics.com/cad/STEP/217-4156-STEP-20140806.zip